Mixing valve for a contrast therapy system

ABSTRACT

The present invention relates to fluid mixing valves, and more particularly, to mixing valve assemblies which incorporate a ball element and which are adapted for use in a thermal or contrast therapy system, or medical thermal therapy system. The ball element of the present invention is characterized by continuously varying restrictive inlets which enable the user to obtain a substantially linear therapy temperature profile while maintaining substantially constant outlet pressure and flow rates.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. application Ser. No. 10/267,247filed on Oct. 8, 2002 now U.S. Pat. No. 7,211,104, entitled “ContrastTherapy System and Method”, which is hereby fully incorporated byreference.

TECHNICAL FIELD

The present invention relates to fluid mixing valves, and moreparticularly, to mixing valve assemblies which incorporate a ballelement and which are adapted for use in a thermal or contrast therapysystem, or medical thermal therapy system. The ball element of thepresent invention is characterized by continuously varying restrictiveinlets which enable the user to obtain a substantially linear therapytemperature profile while maintaining substantially constant outletpressure and flow rates.

BACKGROUND OF THE INVENTION

Numerous thermal therapy devices that apply external treatments to thebody are known in the art. Thermal or contrast therapy devices deliveror remove heat to a given therapy area for an effective amount of timein order to achieve a desired therapeutic result. Contrast therapydevices are used to reduce swelling or to encourage healing afterswelling has receded. They are also used to soothe muscle and joint painthrough the application of heat and compression therapy. Application ofheat or cold may be used to heal and rehabilitate injuries to bone,muscle, ligaments, tendons and skin. Cold therapy may be used to reduceswelling, decrease pain, and promote healing of injured tissue. Heattherapy can be used to relax joint tissue, such as ligaments andtendons, to increase range of motion. Thermal therapy can also be usedafter surgery to reduce pain and swelling and promote healing.

While applying hot and/or cold to sore body parts as therapeutictreatment is well known, the ability to effectively control the therapytemperature of the particular treatment has been problematic. Thepotential effectiveness of a hot or cold treatment increases as thelevel of control for the treatment increases. In particular, theeffectiveness depends on the ability to control the temperature. If coldtreatments are too cold, they may cause skin and tissue damage.Similarly, if hot treatments are too hot, they may burn or otherwisedamage the recipient. Therefore, systems for precisely controlling thetemperature of a therapy are desirable.

Prior art devices have been developed to deliver hot or cold fluids fortherapeutic purposes. For example, U.S. Pat. No. 6,551,347 discloses aheat exchange splint and control unit with a single fluid reservoir anda mixing valve that receives a single input fluid and selectivelydiverts a first portion of the input fluid to a heat exchanger, while asecond portion is diverted past the heat exchanger. The fluid portionsrecombine at a Y junction, and the temperature of the combined fluid isdetermined by the relative amount of fluid diverted to the heatexchanger compared to the amount of fluid bypassing the heat exchangerand flowing straight to the Y junction. The temperature of the combinedfluid may be set as low as the heat exchanger permits and may achieve amaximum temperature equal to the ambient temperature of the surroundingenvironment.

Prior art devices have also been developed to alternately deliver hotand cold fluids for therapeutic purposes. For example, U.S. Pat. No.6,295,819 discloses a thermoelectric heat pump fluid circuit with asingle fluid reservoir and a valve that may be selectively toggledbetween two positions for delivering either a hot or cold fluid. Theposition of the valve determines which of two fluid temperatures areoutput by controlling the direction of fluid flow around a heat pump.When the valve is switched, the temperature of fluid in the systemgradually shifts form one of two possible therapy temperatures to theother.

The prior art devices do not provide a means for incrementallycontrolling the output temperature of the therapy fluid supplied to acompressive heat therapy device. Furthermore, there remains a need for athermal therapy system which includes a means for achieving linearcontrol of the output temperature of a therapy fluid. Previous effortsto provide thermal therapy have included U.S. Pat. No. 2,531,074 whichprovides a therapy pad wherein heated or cooled water is alternatelyinjected. U.S. Pat. No. 4,149,529 also teaches delivering hot or coldfluid to a compressive therapy device. U.S. Pat. No. 4,756,299 providesa heating pad with various sized holes on its opposite sides. The twosides offer the therapy recipient two different temperatures at which touses the product.

Systems that can achieve a desired set temperature and do so rapidly,can further increase the benefit of the applied therapy. This is becausesuch systems can be used to avoid the onset of reflex vasodilatationwhile still giving the analgesic benefits of vasoconstriction. Coldtherapy temperatures as high as 40-50 degrees Fahrenheit may inducevasodilatation as the body attempts to warm the effected area. This isknow as the ‘hunting effect.’ In order to avoid the hunting effect, butstill gain the analgesic benefits of vasoconstriction, a carefullyselected cold therapy temperature must be achieved. Generally, a coldtherapy temperature of about 55 degrees Fahrenheit will give thebenefits of vasoconstriction while avoiding the hunting effect, however,this temperature can vary according to each individual's physiology.

While the above described therapy pads provide for thermal therapy, theyare not effective at providing a convenient mixing valve means forcontrolling the temperature of the delivered therapy fluid. Previousefforts do not provide for linear control of therapy fluid temperatureover the range of achievable temperatures. Known thermal therapy mixingvalves are only effective at controlling therapy fluid temperatures atthe high and low temperature extremes. There remains a need for athermal therapy system with a mixing valve assembly capable of providingincremental control of therapy fluid temperature changes giving a lineartemperature profile over the full range of therapy temperatures.

SUMMARY OF THE INVENTION

To achieve the foregoing and in accordance with the present invention,thermal therapy system mixing valve assemblies and methods for providinga temperature regulated fluid are provided. Such systems are useful forproviding effective thermal therapy through precise temperature controlof therapy fluid.

According to one aspect of the present invention, a thermal or contrasttherapy system includes a hot reservoir for holding a relatively hotfluid and a cold reservoir for holding a relatively cold fluid. Thesystem also includes a mixing valve for receiving a selected ratio ofthe hot and cold fluids from the hot and cold reservoirs. The mixingvalve is operable to deliver a therapy fluid with a therapy temperaturedetermined by the selected ratio. The system also includes a therapy padfor receiving the therapy fluid form the mixing valve and returning thetherapy fluid to at least one of the hot reservoir and the coldreservoir.

In one embodiment, the system includes a mixing valve assembly operableto deliver a therapy fluid with a therapy temperature determined by aselected ratio of relatively high temperature and relatively lowtemperature fluids. The assembly includes an incrementally positionableball vale element having an adjustable rotational position in theassembly. The ball has a first inlet and a second inlet for high and lowtemperature fluids, respectively. The ball also has a mixing chamber influid communication with both inlets, and an outlet in fluidcommunication with the mixing chamber. In this embodiment, the selectedratio of high and low temperature fluids is determined by the rotationalposition of the ball.

In another embodiment, the selected ratio and, by extension, therapyfluid temperature (hereinafter “therapy temperature”) is incrementallycontrolled by adjusting the rotational position of the ball. In thisembodiment, the incremental rotation of the ball produces asubstantially liner change in therapy temperature over time.

In yet another embodiment of the instant invention, the first and secondinlets are substantially wedge shaped. The inlets are characterized by awide forward edge and a narrow rear apex. Preferably, the second inletis larger than the first inlet. More preferably, the second inlet issubstantially larger than the first inlet.

In another aspect of the present invention, the ball element is furthercharacterized by spaced apart interior restrictor walls defining distalinlet chambers and an interior mixing chamber. The restrictor walls actto channel the high and low temperature fluids from the inlet chambersto the mixing chamber. The restrictor wall defining the low temperaturefluid inlet chamber extends further around the interior of the mixingvalve than the wall defining the high temperature fluid inlet chamber.

In a preferred embodiment, the wide forward edge of the first wedgeshaped inlet forms a 5° opening at the surface of the mixing ball, whilethe wide forward edge of the second wedge shaped inlet forms a 15°opening. In this embodiment, both wedged inlets extend 140° around thesurface of the ball.

The present invention also provides a method for supplying atemperature-regulated fluid to a therapy recipient. The method includesproviding a volume of fluid at a relatively high temperature, providinga fluid at a relatively low temperature, and providing a fluid pathwayfor each fluid. The fluid pathway passes through a mixing valve assemblyincluding an incrementally positionable ball element. The methodincludes incrementally adjusting the rotational position of the ball togive linear control of the therapy temperature over a given temperaturerange. Preferably, the temperature range extends from the temperature ofthe low temperature fluid to the temperature of the high temperaturefluid.

Note that the various features of the present invention described abovecan be practiced alone or in combination. These and other features ofthe present invention will be described in more detail below in thedetailed description of the invention and in conjunction with thefollowing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1 is an isometric view of one embodiment of the contrast therapysystem in accordance with the present invention.

FIG. 2 is a schematic view of a fluid circuit for administering contrasttherapy in accordance with an embodiment of the present invention.

FIG. 3 is an isometric view of the fluid circuit of FIG. 2 housed withinthe lid portion of the contrast therapy system of FIG. 1.

FIG. 4 is an isometric view of a fluidic coupling assembly in accordancewith an embodiment of the present invention.

FIG. 5 is an isometric view of a contrast therapy pad in accordance withan embodiment of the present invention.

FIG. 6 is a cross-sectional view of a portion of the contrast therapypad of FIG. 5.

FIG. 7 is an isometric view of a therapy pad wrapped around a therapyrecipient.

FIG. 7A is a cross-sectional view of the therapy pad of FIG. 7 wrappedaround the therapy recipient.

FIG. 8 is a plan view of a contrast therapy pad in accordance with anembodiment of the present invention.

FIG. 9 is an illustration of a method for administering contrast therapyto a therapy recipient in accordance with an embodiment of the presentinvention.

FIG. 10 is an isometric view of a ball element in accordance with anembodiment of the present invention.

FIG. 11 is a plan view of a ball element in accordance with anembodiment of the present invention.

FIG. 12A is a plan view of a ball element in accordance with anembodiment of the present invention indicating cross sectional views 12Aand 12B.

FIG. 12B is a cross-sectional view of a portion of the ball element ofFIG. 12.

FIG. 12C is a cross-sectional view of a portion of the ball element ofFIG. 12.

FIG. 13 is a schematic view of a mixing valve assembly in accordancewith an embodiment of the present invention.

FIG. 14 is a graph illustrating the change in temperature over time of atherapy fluid exiting a mixing valve assembly element.

FIG. 15 is a graph illustrating the change in temperature over time of atherapy fluid exiting a mixing valve assembly element in accordance withan embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference toa few preferred embodiments thereof as illustrated in the accompanyingdrawings. In the following description, numerous specific details areset forth in order to provide a thorough understanding of the presentinvention. It will be apparent, however, to one skilled in the art, thatthe present invention may be practiced without some or all of thesespecific details. In other instances, well known process steps and/orstructures have not been described in detail in order to notunnecessarily obscure the present invention. The features and advantagesof the present invention may be better understood with reference to thedrawings and discussions that follow.

To facilitate discussion, FIGS. 1 through 8 show various views of thepresent contrast therapy system. FIG. 9 provides an illustration of amethod for providing contrast therapy to a therapy recipient. FIGS. 10through 14B provide various views of the present mixing valve assemblyand the present ball element. FIGS. 15 through 17 show graphsillustrating the change in temperature over time of a therapy fluidexiting a mixing valve assembly element in accordance with variousembodiments of the present invention.

The present invention relates to a contrast therapy system and a methodof providing contrast therapy. An embodiment of the present invention isshown generally at 10 in FIG. 1. Although useful for applying anycombination of heat, cold, and compression, to a recipient for virtuallyany reason, the contrast therapy system described below demonstratesparticular utility for treating sore, strained, arthritic, injured,heavily exercised, and/or otherwise taxed body parts. The contrasttherapy system is described below in the context of providing “therapy”to a recipient, however, it should be understood that the contrasttherapy system is equally well suited for providing any combination ofheat, cold, and compression for what may be considered non-therapeuticpurposes.

As described herein, the contrast therapy system is capable of impartinga desired therapy temperature to a therapy pad 22, which may be appliedto a therapy recipient. The system is capable of shifting the therapytemperature between hot and cold temperatures very quickly, which hasproven to be beneficial. The precise temperature may be set at anytemperature between controlled maximum and minimum temperatures. Thesystem is also capable of applying compressive force to a therapyrecipient, thus increasing the effectiveness of treatments. Furthermore,the contrast therapy system may be designed as a relatively smallportable unit, as shown at 30 of FIG. 1, which is both easy andinexpensive to operate.

Fluid Circuit

FIG. 2 schematically shows a fluid circuit of a contrast therapy system10, and FIG. 3 shows such a circuit housed by a lid 28 of a portablecontrol unit 30. As illustrated in FIGS. 2 and 3, contrast therapysystem 10 includes a cold reservoir 12, hot reservoir 14, mixing valve16, pump 18, fluidic coupling assembly 20, and therapy pad 22. Asdescribed in detail below, the contrast therapy system is designed tocontrol the temperature of a therapy fluid that circulates throughtherapy pad 22. Mixing valve 16 selectively combines fluid received fromthe cold and hot reservoirs and passes the combined fluid to the therapypad as a therapy fluid. The mixing valve may control the temperature ofthe therapy fluid, changing between hot and cold temperatures in a shortperiod of time.

Cold reservoir 12 is designed to hold a relatively cold fluid, which maybe passed to a mixing valve and eventually to a therapy pad. As shown inFIG. 1, cold reservoir 12 may include a container 24 with an open end 26suitable for receiving a lid 28. The container and the lid may becomponents of the control unit. The cold reservoir may be dimensioned tohold virtually any volume of fluid, and is shown as a 4.2 Literreceptacle. Of course, smaller cold reservoirs may be used, for example,when increased portability is desired, and larger cold reservoirs may beused when, for example, increased capacity is desired.

The temperature of the cold reservoir may be controlled by variousmechanisms. In some embodiments, the cold reservoir is adapted toreceive ice that may melt in the cold reservoir, and thus decrease thetemperature of the fluid in the cold reservoir. As shown in FIG. 1,container 24 has a large open end 26 that is suitable for easilyreceiving ice. In some embodiments, the cold reservoir may include acooler for cooling the fluid held in the cold reservoir. Such a coolermay include a compressor and a refrigerant, or similar coolingmechanism. It is within the scope of the invention, however, to usevirtually any other suitable method for cooling the fluid held in coldreservoir 12. The cold reservoir may include insulation to limit heattransfer between the fluid held by the cold reservoir and the externalenvironment.

The minimum temperature of the fluid in cold reservoir 12 is usuallylimited to approximately 32 to 45 degrees Fahrenheit, although such alimitation is not necessary. In particular, it has been found that atemperature of about 35 to 42 degrees Fahrenheit is an appropriateminimum temperature. Although water is usually used as the fluid, it iswithin the scope of the invention to use other suitable fluids. Suchfluids may be selected for particular applications based on theirspecific heat, viscosity, freezing point, etc.

Contrast therapy system 10 may include an intake 32 for drawing fluidfrom the cold reservoir. The drawn fluid may pass through a fluid path34 between cold reservoir 12 and mixing valve 16, as is schematicallyshown in FIG. 1. Fluid path 34, as well as other fluid paths describedherein, may utilize ⅛ inch flexible tubing, or may alternativelyimplement another suitable fluid transport mechanism. For example, someor all of the fluid paths may alternatively be defined by inflexiblefluid conduits. The fluid paths, or other fluid channels such as intake32, may include filters, flow restrictors, and/or check valves. Filtersmay help prevent flow blockages resulting from jammed ice or othersubstances, and check valves may be used to prevent backflow in thesystem. The rate of fluid flow may be at least partially controlled byflow restrictors.

Hot reservoir 14 is designed to hold a relatively hot fluid, which maybe passed to a mixing valve and eventually to a therapy pad. Fluid inthe hot reservoir may be heated by a heater 36, which may be positionedadjacent the hot reservoir, or may be incorporated into the hotreservoir. The hot reservoir may be dimensioned to hold virtually anyvolume of fluid, and is shown dimensioned to hold a volume ofapproximately 20 to 30 cubic centimeters. It should be understood thatthe hot reservoir may be smaller or larger, depending on the desired useand the other components of the contrast therapy system.

Heater 36 may be configured so as to achieve a suitable balance of powerconsumption and heat generation. It has been found that a heater ofapproximately 280 Watts is appropriate for heating a volume ofapproximately 20 to 30 cubic centimeters under normal conditions. Itshould be understood that more powerful and less powerful heaters may beused. Similarly, more than one heater or type of heater may be used.

The flow rate of fluid through the hot reservoir may correspond to thetemperature of treatment being applied, with greater flow ratesoccurring during hotter treatments. During some hot treatments, heater36 may have limited time to increase the temperature of the fluidbecause the fluid quickly passes through the hot reservoir, and thus,the heater should be powered so as to increase the temperature a desiredamount within that constrained timeframe. However, the heater does notneed to completely heat the fluid from a minimum temperature to amaximum temperature in such a timeframe, although it is within the scopeof the invention to do so. The hot reservoir receives fluid from thetherapy pad, and when a hot treatment is being applied, the return fluidmay already be partially heated, decreasing the magnitude of heatingrequired from heater 36. Thus, the net temperature of the fluid mayincrementally increase as it repeatedly circulates through the hotreservoir. Nevertheless, a more powerful heater may increase the ratefluid increases temperature in the hot reservoir and/or the maximumtemperature of the fluid, thus decreasing the time required to changefrom a cold treatment to a hot treatment. The maximum temperature of thefluid in hot reservoir 14 is usually limited to approximately 100 to 110degrees Fahrenheit, although such a limitation is not required. Inparticular, it has been found that a temperature of about 105 degreesFahrenheit is appropriate.

As illustrated in FIGS. 2 and 3, hot reservoir 14 receives fluid via afluid path 38 coming from a bulkhead input 40. As described below,bulkhead input 40 receives fluid returning from the therapy pad. Thereturning fluid may be directed so that fluid may go to at least one ofthe hot reservoir, via fluid path 38, and the cold reservoir, via areturn 52. In some embodiments, the hot reservoir may be housed withinlid 28, which may be securely fit to open end 26 of container 24. Heater36 may be controlled by an internal control system, external controlsystem, or no control system whatsoever. If present, a control systemmay regulate the maximum temperature of fluid in the hot reservoir, forexample. Such a control system may also be designed to maximize heatingefficiency to limit energy requirements.

Mixing Valve

Contrast therapy system 10 includes a mixing valve 16 for receiving aselected ratio of the hot and cold fluids from the hot and coldreservoirs. The mixing valve is operable to deliver a therapy fluid witha therapy temperature that is determined by the selected ratio. In otherwords, mixing valve 16 may adjustably control the amount of hot fluidfrom the hot reservoir and the amount of cold fluid from the coldreservoir that mix together. The ratio may be 100% hot fluid from thehot reservoir, in which case the resulting therapy fluid would have atherapy temperature substantially equal to the temperature of fluidleaving the hot reservoir (maximum temperature). The ratio mayalternatively be 100% cold fluid from the cold reservoir, in which casethe resulting therapy fluid would have a therapy temperaturesubstantially equal to the temperature of fluid leaving the coldreservoir (minimum temperature). Any temperature in between the maximumand minimum temperature may be achieved by adjusting the ratio.

The mixing valve is linked to the cold reservoir and the hot reservoirby respective fluid paths 34 and 42. In some embodiments, one or both offluid paths 34 and 42 may include a pump, although no pump is required.The mixing valve outputs therapy fluid to a fluid path 44 that leads tothe bulkhead output 46, and eventually to therapy pad 22. A pump may beincluded between the mixing valve and the therapy pad, as shown in FIGS.2 and 3 and described below. As with the other fluid paths of thecontrast therapy system, these fluid paths may include flow restrictors,check valves, filters, over-pressure switches, and/or other components.For example, check valve 31 and over pressure switch 33 are illustratedin FIG. 3. The flow paths may include flexible rubber tubing that isapproximately ⅛ inch in diameter.

As shown in FIG. 1, the mixing valve may be controlled by a dial 48 thatadjusts the ratio of hot and cold fluids delivered from the mixingvalve. The dial may be associated with indicia 50 that indicate arelative magnitude of a desired therapy temperature. For example,indicia 50 may include a series of icons representing relativetemperatures. A large red dot may represent the hottest therapytemperature, with red dots decreasing in size representing decreasingtemperatures. Similarly, a large blue dot may represent the coldesttherapy temperature, with blue dots decreasing in size representingincreasing temperatures. A dial positioned to point to the large red dotmay correspond to a mixing valve position that yields a ratio of 100%hot fluid. As the dial is turned through the progressively smaller reddots, and then through the progressively larger blue dots, the ratio mayyield a therapy fluid with a continually increasing percentage of coldfluid.

In some embodiments, the contrast therapy system may include athermostat that automatically selects the ratio of hot and cold fluidsdelivered from the mixing valve. For example, the thermostat may bedesigned to receive manual input of a desired therapy temperature, andadjust the mixing valve to yield a therapy fluid with that temperature.Accordingly, the thermostat may include a temperature measuring device(not shown), such as a thermistor, thermometer, thermocouple, etc. Thetemperature measuring device may monitor the temperature of the therapyfluid as the thermostat adjusts the mixing valve to yield the desiredtherapy temperature. The temperature measuring device may cooperate witha temperature display to present the temperature of the therapy fluid.The thermostat may be programmable to automatically change the therapytemperature at a desired time or event by adjusting the ratio of hot andcold fluids delivered from the mixing valve. For example, the thermostatmay be programmed to provide alternating hot therapies that last forfive minutes at 105 degrees Fahrenheit and cold therapies that last for5 minutes at 40 degrees Fahrenheit. It should be understood that thethermostat may be programmed for therapies of different durations and/ortemperatures.

As shown in FIGS. 2 and 3, contrast therapy system 10 may include a pump18 for circulating fluid through the system. As illustrated, the pumpinterposes the mixing valve and the bulkhead output, although the pumpmay be positioned elsewhere. Similarly, more than one pump may beutilized. As is shown, the pump may be integrated into the lid of thecontrol system. The pump may be powered according to the desiredapplication, and a 4 Watt pump capable of pumping 300 cubic centimetersof fluid per minute has been found to be suitable. The pump may be areciprocating pump, a rotary pump, or virtually any other suitable pump.

In some embodiments, the pump may be configured to pulse the therapyfluid through the therapy pad. Such a pulsing action may be translatedinto a therapeutic massage via the therapy pad. As the pulsing fluidcirculates through the therapy pad, the therapy pad may vibrate. Pumpsdesigned to pulse fluid may be further enabled to adjust the relativemagnitude of the pulsing to correspond to different intensities oftherapeutic massages. The relative intensity may be automatically, ormanually, coordinated to correspond to a particular temperature oftreatment. For example, a vigorous massage may be applied during a hottreatment while a milder massage is applied during a subsequent coldtreatment.

Fluidic Coupling Assembly

Contrast therapy system 10 may include a fluidic coupling assembly 20 toselectively couple and decouple the mixing valve and the therapy pad. Asshown in FIG. 4, the fluidic coupling assembly usually includes abulkhead 54, which is in fluid communication with the mixing valve, awrap connector 56 in fluid communication with therapy pad 22, and areversible tubing assembly 58 for linking the bulkhead to the wrapconnector. The reversible tubing assembly includes a first tube-setconnector 60 and a second tube-set connector 62 that are functionallyequivalent to one another. First tube-set connector 60 and secondtube-set connector 62 are linked by fluid paths 64 and 66.

Bulkhead 54, first tube-set connector 60, second tube-set connector 62,and wrap connector 56 each include one male valve and one female valve,which are configured to mate with a corresponding female and male valve,for example, as shown by dotted lines 57 in FIG. 4. The bulkhead and thewrap connector are each configured to releasably receive either thefirst tube-set connector or the second tube-set connector. Therefore,tubing assembly 58 is completely reversible. For example, the bulkheadand the first tube-set connector may be coupled so that the bulkhead'smale valve mates with the first tube-set connector's female valve, andthe bulkhead's female valve mates with the first tube-set connector'smale valve. Likewise, the wrap connector and the second tube-setconnector may be coupled so that the wrap connector's male valve mateswith the second tube-set connector's female valve, and the wrapconnector's female valve mates with the second tube-set connector's malevalve. Because the tubing assembly is reversible, the above describedconnection may be reversed. For example, if the first tube-set connectoris connected to the bulkhead, the second tube-set connector is availablefor connection to the wrap connector, but if the second tube-setconnector is connected to the bulkhead, the first tube-set connector isavailable for connection to the wrap connector. In either case, sucharrangements permit fluid to flow from the control unit to the therapypad, and then return back to the control unit.

The male and female valve of each of the above described components areequally spaced from one another. Therefore, male and female valves fromone component may align with female and male valves from a correspondingcomponent. Furthermore, bulkhead 54 is complementarily configuredrelative to both the first and second tube-set connectors to facilitatesecuring either the first tube-set connector or the second tube-setconnector to the bulkhead. Similarly, either the first tube-setconnector or the second tube-set connector may be secured to the wrapconnector. The male and female valves are designed to prevent fluid flowunless they are mated with one another, thus limiting leakage whendisconnecting the reversible tubing assembly from the control unitand/or the therapy pad.

The configuration of the fluidic coupling assembly facilitates easyconnection and disconnection of a plurality of control units, tubingassemblies, and/or therapy pads. For example, the same control unit maybe used with a variety of different therapy pads, which may beindividually configured to treat different areas of a recipients body.Similarly, a single therapy pad may be used with a variety of differentcontrol units, for example, when a recipient moves from one therapylocation to another. The fluidic coupling assembly facilitates quick andeasy coupling and decoupling, and the leak reducing male and femalevalves help limit spillage during such coupling and decoupling.

Therapy Pad

FIG. 5 shows therapy pad 22 apart from the remainder of the contrasttherapy system. As described above, the therapy pad may be easilycoupled and decoupled from the reversible tubing assembly, which allowsvarious different therapy pads to be used with the same control unit.Each therapy pad is designed to receive therapy fluid from the mixingvalve, such as through the fluidic coupling assembly, and return thetherapy fluid to at least one of the hot reservoir and the coldreservoir (as shown schematically in FIG. 2). The therapy pad returnsfluid to the control unit, and the returned fluid may be recirculated.Depending on the type of therapy being applied, returned fluid may beheated and/or cooled at the control unit. The contrast therapy systemmay include a return valve that selectively directs return fluid to thehot reservoir and/or the cold reservoir, or the return fluid may beallowed to naturally flow to the lower pressure region.

In some embodiments, the therapy pad includes an active thermal exchangebladder 68 and an elastic wrap 70 that is connected to the thermalexchange bladder. The thermal exchange bladder may include a flexiblemembrane of opposing faces that are welded together to define a channelsystem for directing the flow of therapy fluid along a desired fluidpath 72 within the thermal exchange bladder. For example, the faces areusually welded along a common outer perimeter 74, sealing the facestogether. A division weld 76 may direct fluid through a substantialportion of the pad before returning to the control unit. The thermalexchange bladder may also include a plurality of intermittent welds 78,that limit inflation of the bladder, as shown in FIG. 6, which is across-sectional view of a portion of the exchange bladder.

The thermal exchange bladder facilitates thermal exchange between atherapy site and the therapy fluid. For example, when a cold therapy isadministered, heat from a recipient's body may heat the therapy fluid,which in turn cools the therapy site. Similarly, when a hot therapy isadministered, the therapy fluid may transfer heat to the therapy site.The therapy may be enhanced by moistening the bladder to provide a moisttherapy. Furthermore, the fluid may also be pulsed through the bladder,adding a therapeutic massage aspect to the treatment.

In the illustrated embodiment, therapy pad 22 is dimensioned to holdapproximately 150 cubic centimeters of fluid. However, the volume of thetherapy pad may be controlled by changing the size of the therapy pad,and/or the amount of inflation the intern littent welds allow.Furthermore, the therapy pad may be constructed from an at leastpartially elastic material, such as urethane, which may permit thevolume to change in response to the pressure of fluid within thebladder. In some embodiments, the bladder may include a less elasticmaterial that helps prevent stretching, such as a vinyl/urethane blend.

As shown in FIG. 5, fluid may enter the bladder at wrap connector 56,flow around the division weld and the intermittent welds, and leave thebladder at the wrap connector. It is within the scope of the inventionto reconfigure the bladder to accommodate different flow paths. Forexample, the division weld, or plural division welds, may be used todirect the fluid through a series of switchbacks before returning to theoutput of the wrap connector. Small breaks may be included in thedivision weld to permit alternative flow paths if a primary flow path isblocked.

Elastic wrap 70 is shown connected to the thermal exchange bladder. Theelastic wrap may be configured to adjustably wrap around the thermalexchange bladder and compress the thermal exchange bladder around atherapy site. Compression helps induce contact of the bladder with thetherapy site, which may promote efficient and even thermal transfer.Furthermore, the wrap is a compressive element in and of itself. Whenused in conjunction with the bladder, it keeps the bladder in contactwith the therapy site, and it may also help reduce swelling through itsown inherent compressibility. The wrap is continuously adjustable,meaning it may be repeatedly tightened and loosened to various levels ofcompression, as shown in FIG. 7. The wrap may be used in tandem with thebladder to wrap a therapy site in a variety of ways, thus providingextreme flexibility in the types of treatments that may be administeredto a wide range of different therapy sites.

Wrap 70 is elastic; it may be stretched and naturally return to anunstretched disposition. When stretched, the wrap is at an increasedtension, which may be used to compress a therapy pad around a therapysite, as shown in FIG. 7A. Force vectors 80 schematically represent thecompressive force resulting from the wrap. The magnitude of thecompressive force may be selected by adjusting the amount the wrap isstretched. As the wrap is increasingly stretched around a therapy site,the compressive force the wrap applies increases. Similarly, the wrapmay be loosened, decreasing the magnitude of the compressive force. Theamount of elasticity a particular wrap has may be selected according toa desired application, or range of applications. In some embodiments,the wraps are designed to stretch to approximately 150%-200% of theirunstretched length, however less elastic and more elastic wraps may beused. The wraps may be variously sized, and are usually at least as longas their corresponding bladder when unstretched. As illustrated in FIG.5, the unstretched wrap is six times as long (54 inches) as the bladder(18 inches). Because of the elastic configuration of the wrap, wrappingtechniques known to physical therapists, physical trainers, and sportsphysicians may be used in conjunction with the therapy pad to achieve awide variety of therapeutic benefits.

As shown in FIG. 5, elastic wrap 70 is permanently connected to thermalexchange bladder 68. The wrap may be connected by stitching, anadhesive, and/or another suitable fastener. In some embodiments, thebladder is connected to the wrap via an optional mesh envelope, shown indashed lines at 69. In such embodiments, the envelope may be permanentlyconnected to the wrap, and the bladder may be selectively positionedwithin the mesh envelope. The mesh envelope may include a fastening faceconfigured to selectively fasten with a complimentary fastener of thewrap. The wrap may alternatively be removably connected to the bladder,such as by hook and loop connectors. By permanently connecting the wrapto the bladder, such as by stitching or configuring an envelope tosecurely hold the bladder relative to the wrap, the wrap and the bladdermay cooperate to provide a compressive force, as described herein.Furthermore, the combination has proven to be much easier to apply thanseparated therapy pads and wraps, and thus is more versatile.

The wrap usually includes a surface of loops 82 that are adapted todetachably receive complementary hooks 84. The hooks and loops arepositioned, so that the hooks may engage the loops when the wrap iswrapped around a therapy site, as shown in FIGS. 7 and 7A. The wrap maybe adjusted to a desired tension and a corresponding level ofcompressive force that may be fixed by engaging the hooks and the loopstogether. The hooks and loops may subsequently be disengaged, so thatthe tension may be adjusted, for instance, and reengaged at will. Insome embodiments, a wrap lock may alternatively be used to secure thewrap.

In some embodiments, the therapy pads may be constructed with disposablematerials. For example, pads configured for a single use may beconstructed from disposable materials, which are usually less expensivethan reusable materials. Disposable therapy pads may be particularlyuseful in emergency, trauma, or post surgery situations, in which atherapy recipient may bleed onto the therapy pad. The ability to controlthe temperature of the therapy pad, either reusable or disposable, mayincrease the pad's effectiveness as a wound dressing. Disposablematerials may include less resilient versions of reusable materialsand/or completely different materials. In some embodiments, disposablematerials may include apertured, breathable, elastomeric and/or embossedfilms, as well as nonwoven laminates. Wraps may alternatively beconfigured to be washable, such as by a laundry machine, and thereforemay be sanitarily reused.

The thermal exchange bladder may be sized and shaped according to aparticular range of applications. For example, a 6 inch by 18 inchbladder (as shown at 22 in FIG. 5) may be useful in treating backs,legs, arms, shoulders, and other therapy sites. Although the versatileconfiguration of therapy pad 22 may be used for virtually any therapysite, other therapy pads may be configured to even better accommodateparticular therapy sites. For example, a 2 inch by 18 inch bladder 86,as shown in FIG. 8, may be particularly useful for treating smallertherapy sites, such as hands, wrists, feet, ankles, etc. Similarly, ashoulder therapy pad may be designed to intimately engage a shouldertherapy site, thus providing comfortable and improved treatment. A jawtherapy pad, which is useful in treating the facial area, may bedesigned to comfortably wrap around a head, while positioning a bladderin contact with at least one side of a jaw. It should be understood thatthe above therapy pads are provided as examples, and other therapy padsmay also be used. Furthermore, each therapy pad may include a suitableelastic wrap and/or other fastening mechanism.

The therapy system may be used to treat a wide range of conditions,including injured muscles, bones, joints, tendons, ligaments etc.Furthermore, other conditions may be treated, such as mastitis orbreasts that are sore from menstruation. The therapy system may also beused as a preventative remedy, for example the therapy system may beused during child birth to help alleviate discomfort during labor aswell as help minimize resulting soreness and/or discomfort. For example,providing a cold treatment to a recipient's back during child birth mayhelp cool the recipient, thus alleviating immediate discomfort, as wellas subsequent soreness.

Contrast therapy system 10 may include a power supply, such as 92 ofFIG. 3, for providing power to various components of the system, such asa heater, cooler, pump, thermostat, display, etc. In some embodiments,the power supply may provide alternating current, while in otherembodiments, the power supply may provide direct current. Someembodiments may be configured to operate with either AC or DC power. Forexample, the contrast therapy system may include a DC heater and pumpdesigned to draw power from either a battery or an electrical outlet viaan AC/DC converter. Batteries used to power the contrast therapy systemmay be externally connected to the system, and/or housed within thesystem. The contrast therapy system may be powered from alternativepower sources as well.

Method of Administering Contrast of Thermal Therapy

FIG. 9 shows, generally at 100, a method of administering contrasttherapy to a therapy recipient. Method 100 includes, at 102, providing avolume of a relatively hot fluid. As explained above, a fluid may bereceived by a hot reservoir, where it may be heated by a heater. Therelatively hot fluid may be virtually any temperature, with temperaturesof approximately 100 to 105 degrees Fahrenheit being suitable for manyapplications. The method further includes, at 104, providing a volume ofa relatively cold fluid. Fluid may be received by a cold reservoir,where it may be cooled. In some embodiments, an ice slurry is used tocool fluid passing through the cold reservoir, and in some embodiments acooler is used. The cold fluid may be virtually any temperature (coolerthan the hot fluid), with temperatures of approximately 32 to 45 degreesFahrenheit being suitable for many applications.

At 106, the method includes selecting relative amounts of the hot andcold fluids to mix as a therapy fluid with a desired initial therapytemperature. A mixture of hot and cold fluids with a specific ratio maybe selected with a mixing valve, or similar mechanism, that isconfigured to receive the hot and cold fluids, and pass the mixture ofthe hot and cold fluids as a therapy fluid. The ratio of hot to coldfluid in the therapy fluid may range from 100% hot fluid to 100% coldfluid, as well as any intermediate ratio. The temperature of the therapyfluid corresponds to the ratio of hot and cold fluids mixed, withgreater percentages of hot fluid resulting in higher temperatures, andgreater percentages of cold fluid resulting in cooler temperatures. Thetherapy fluid's maximum temperature is approximately the temperature ofthe hot fluid, and is achieved by selecting a ratio of all hot fluid andno cold fluid. Similarly, the therapy fluid's minimum temperature isapproximately the temperature of the cold fluid, and is achieved byselecting a ratio of all cold fluid and no hot fluid.

As shown at 108, the method further includes circulating the therapyfluid with the initial therapy temperature through a therapy pad. Thetherapy fluid may be circulated in a pulsing stream, so as to impart avibration that is useful in providing a therapeutic massage. Of course,the flow may instead be smooth. At 110, the method includes applying thetherapy pad to the therapy recipient. The temperature of the therapyfluid may be translated through the therapy pad to the therapyrecipient. For example, if the initial temperature of the therapy fluidis relatively hot, for instance 105 degrees Fahrenheit, the therapy padmay be used to heat a therapy site on the therapy recipient. Similarly,a therapy fluid with a relatively cold therapy temperature, such as 40degrees Fahrenheit, may be used to cool a therapy site. The pad may beapplied to a therapy recipient by using an integrated elastic wrap tocompress the therapy pad around a therapy site, which may add to thebenefits of the treatment.

The method further includes, at 112, returning the therapy fluid to atleast one of the volume of hot fluid and the volume of cold fluid.Returning the therapy fluid to either or both of the volumes of hot andcold fluids allows the therapy fluid to be recycled. The returnedtherapy fluid may then be heated and/or cooled, and eventually may berecirculated to the therapy pad. In this manner, a limited volume offluid in a system may be used to provide an ongoing therapy. The fluidmay be repeatedly heated and/or cooled, and thus the character of thetreatment may be continually changed.

As shown at 114, the method may also include selecting relative amountsof the hot and cold fluids to mix as a therapy fluid with a desiredcontrast therapy temperature different than the initial therapytemperature. By changing the relative amounts of hot and cold fluids,the resulting temperature of the therapy fluid may be changed, whichchanges the therapy received by the therapy recipient. It is within thescope of the invention to make such temperature changes quickly, such asin under a minute, which may result in an average temperature changegreater than 1 degree Fahrenheit per second. At 116, the method mayfurther include circulating the therapy fluid with the contrast therapytemperature through the therapy pad. Circulating the therapy fluid withthe contrast therapy temperature allows the therapy recipient toexperience a cold treatment immediately after a hot treatment or a hottreatment immediately after a cold treatment. It should be understoodthat the period of change between respective treatments is ideally verysmall, such as under one minute. This process may be repeated one ormore times, and each time the relative amounts of hot and cold fluidsmay be selected to result in a desired therapy temperature.

Mixing Valve Assembly

Mixing valve assembly 1601 selectively combines fluid received from thecold reservoir 12 and hot reservoir 10, and passes the combined fluid tothe therapy pad 22 as a therapy fluid at a selected therapy temperature.As noted above, the mixing valve assemble 1601 is capable of controllingthe temperature of the therapy fluid (hereinafter “therapytemperature”), changing between relatively high and low temperatures ina short period of time. The mixing valve assembly 1601 may control thetherapy temperature by incrementally controlling the amount ofrelatively high temperature fluid received from the hot reservoir 10 andthe amount of relatively low temperature fluid received from the coldreservoir 12 that mix together.

Referring now to FIG. 10, incremental temperature control is achieved byincorporating the ball element 1000 of the instant invention into themixing valve assembly 1601. As shown in FIGS. 11 and 12A, a preferredembodiment of ball element 1000 is characterized by a first inlet 1102and a second inlet 1101. Any number of inlets may be used depending uponthe particular application.

In a preferred embodiment, mixing valve assembly 1601 may advantageouslybe configured to provide relatively high temperature fluid from the hotreservoir 10 to the first (or high temperature) inlet 1102, andrelatively low temperature fluid from the cold reservoir 12 to thesecond (or low temperature) inlet 1101. Incremental control of thetherapy temperature is achieved by adjusting the rotational position ofthe ball element 1000 within the mixing valve assembly 1601. The ballelement 1000 may be rotated about its axis of rotation 1107 to thedesired position.

Referring now to FIG. 12C, first inlet 1102 and second inlet 1101 are influid communication with mixing chamber 1211 which, in turn, is in fluidcommunication with outlet 1212. Fluid may flow from outlet 1212 throughmixing valve assembly 1601 to a selected therapy device. Adjusting therotational position of the ball element 1000, in turn, adjusts the ratioof relatively high and low temperature fluids which pass into the mixingchamber 1211. As a result, the therapy temperature is incrementallycontrolled through incremental rotation of the ball element 1000 aboutits axis 1107. A control stem 1305 may be attached at the ball assemblyactuator receptacle 1210 to effectively control rotational positioning.The control stem may advantageously be connected to a dial 48 whichallows the user to select therapy temperature. Or, alternatively, thestem may automatically be controlled via a servo or some other automaticactuating device.

The selected ratio of relatively high temperature fluid and relativelylow temperature fluid may be 100% hot fluid from the hot reservoir 10 inwhich case the resulting therapy fluid would have a therapy temperaturesubstantially equal to the temperature of the fluid leaving the hotreservoir 10. This would define a high temperature maximum for thetherapy fluid exiting the outlet 1212 of the ball element 1000. Theselected ration may alternatively be 100% cold fluid from the cold fluidreservoir 12 in which case the resulting therapy fluid would have atherapy temperature substantially equal to the temperature of the fluidleaving the cold reservoir 12. This would define a low temperatureminimum for the therapy fluid. Any temperature between the maximum andminimum may be achieved by incrementally adjusting the rotationalposition of the ball element according to the present invention.

Preferably, fluid passes from the hot reservoir 10 through the firstinlet 1102 and into the mixing chamber 1211. If the selected ratio is100% from the hot reservoir 10, then the fluid passes through the outlet1212 to a selected therapy device at substantially the maximum therapytemperature. Similarly, if the selected ratio is 100% from the coldfluid reservoir 12, fluid passes through the second inlet 1101, throughthe mixing chamber 1211 and outlet 1212 to the selected therapy deviceat substantially the minimum therapy temperature. Advantageously, theselected ratio may be chosen to give any temperature from minimum tomaximum therapy temperature.

By incrementally adjusting the rotational position of the ball 1000,relatively high and low temperature fluids may pass through theirrespective inlets at the selected ratio. The fluids are mixed in themixing chamber 1211 and pass through the outlet 1212 at the desiredtherapy temperature. The present invention gives linear control overtherapy temperature changes over the entire range of possible therapytemperatures. The instant ball element allows the user to progressthrough a substantially linear progression of therapy temperatureincreases (or decreases) from minimum to maximum temperature. As aresult, a linear outlet therapy temperature profile may be achieved. Ofcourse, any desired temperature profile (including linear or non-linear)may be achieved using the instant invention.

Known balls do not afford the user linear temperature control over therange of therapy temperatures. Preferably, therapy temperatures rangefrom a minimum of about 40° F. to a maximum of about 105° F.Temperatures below the minimum or above the maximum may cause tissuenecrosis or other tissue damage. As shown in FIG. 14, known balls onlyoffer linear temperature control over a very small range of temperaturesnear the minimum and maximum therapy temperatures.

As can be seen in Table 1, below, therapy fluid temperature near theminimum is quickly overwhelmed by the introduction of high temperaturefluid from the hot reservoir 10. The user is afforded no linear controlover therapy temperature over the majority of the given temperaturerange. The practical effect is that the user may select only a minimum,maximum and intermediate temperature.

TABLE 1 POSITION FLOW INTERVAL THE OF TEMPERATURE RATE PRESSURE OF KNOB(° F.) (ml/min) (Psi) SAMPLING 1 44 193 15 5 mins 2 53 210 16 5 mins 355 220 16.7 5 mins 4 59 208 16.7 5 mins 5 64 215 16 5 mins 6 66 213 16.45 mins 7 69 215 14.4 5 mins 8 71 220 14 5 mins 9 76 216 13.7 5 mins 1082 210 13 5 mins 11 88 202 12.6 5 mins 12 107 193 10 5 mins

Known balls commonly offer a series of bores or holes which act asinlets for both the relatively low and high temperature fluids. A set ofbores for each temperature fluid may range from a relatively small sizehole through progressively larger holes to a relatively large size hole.In the example given by Table 1, above, each series of bores offered thesame size holes for both the hot and cold fluids.

In the instant invention, the ball is modified by replacing the boreswith continuously varying wedge shaped restrictive openings. Table 2,below, is an illustration of the temperature profile of the outlettherapy fluid achieved through the use of the modified ball. The instantwedge shaped inlets give substantially linear temperature control of theoutlet therapy temperature profile. The modified ball offers betterincremental control of therapy temperature.

TABLE 2 POSITION FLOW INTERVAL OF THE TEMPERATURE RATE PRESSURE OF KNOB(° F.) (ml/min) (Psi) SAMPLING 1 44 — — 5 mins 2 55 — — 5 mins 3 57 — —5 mins 4 60 — — 5 mins 5 63 — — 5 mins 6 64 — — 5 mins 7 68 — — 5 mins 872 — — 5 mins 9 77 — — 5 mins 10 77 — — 5 mins 11 86 — — 5 mins 12 105 —— 5 mins

In a preferred embodiment of the instant invention, interior restrictorwalls are added to form inlet chambers at each of inlets 1101 and 1102.When used in conjunction with a relatively hot and a relatively coldinput fluid, the ball element is designed to give complete lineartemperature control over the entire range of available therapytemperatures. As shown in FIG. 15, the instant ball element 1000 allowsthe user to incrementally control changes in therapy temperature fromminimum therapy temperature to maximum therapy temperature. Thisprovides the advantage of allowing for more effective therapy byenabling users to apply the indicated progression of thermal therapytreatment most effective for addressing the presented injury. There isprovided the additional advantage of making the therapy experience morecomfortable to the user. As a result, the user is more likely to followthe indicated therapy regimen.

Table 3, below, is an illustration of the progression of temperaturechanges achieved through the use of the instant ball element 1000 anddepicted in FIG. 15. The user is afforded complete linear control overtemperature changes for the entire range of allowable therapytemperatures.

TABLE 3 POSITION FLOW INTERVAL OF THE TEMPERATURE RATE PRESSURE OF KNOB(° F.) (ml/min) (Psi) SAMPLING 1 45 266 15.7 5 mins 2 47 278 17.5 5 mins3 53 277 18.2 5 mins 4 58 282 16.8 5 mins 5 70 279 14.0 5 mins 6 75 26214.0 5 mins 7 78 266 14.3 5 mins 8 82 268 14.8 5 mins 9 87 255 12.7 5mins 10 89 238 12.5 5 mins 11 97 260 12.1 5 mins 12 105 258 11.6 5 mins

In a preferred embodiment, the inlets of the ball element 1000 of theinstant invention are substantially wedge shaped. The first inlet 1102and second inlet 1101 are characterized by wide forward edges which meetin a pre-mixing zone 1206. Each inlet tapers to a narrow rear apex asillustrated by the second inlet apex 1201. In a another embodiment, thesecond inlet 1101 is larger than the first inlet 1102.

Refereeing now to a more preferred embodiment of the ball element 1000of the instant invention is shown. Said second inlet 1101 issubstantially larger than the first inlet 1102. The wide forward edge ofthe second inlet forms a 15° angle at the surface of the ball element.Whereas, the wide forward edge of the first inlet 1102 forms a 5° angleat the surface of the ball element 1000.

Preferably, the wedge shaped first and second inlets are furthercharacterized by the length of their extension around the circumferenceof the ball element 1000. As shown in FIG. 12B, each inlet extends fromits wide forward edge to its narrow rear apex over an angle γ of 140°.

In a preferred embodiment, the ball element 1000 of the instantinvention includes internal restrictor wall elements. The temperatureprofile achieved with said ball was shown to be substantially linear asshown above in Table 3 and in FIG. 16. Referring now to FIG. 12B, coldrestrictor wall 1227 and hot restrictor wall 1228 act to restrict flowof cold and hot fluids respectively. Restrictor walls 1227 and 1228define a low temperature inlet chamber and a high temperature inletchamber, respectively. The restrictor walls channel fluid entering thefirst and second inlet to a pre-mixing area 1106. The fluids thenprogress to the mixing chamber 1211 where they are mixed to achieve thedesired therapy temperature.

The restrictor walls advantageously act in conjunction with the wedgeshaped inlets to enhance the ability of the instant ball element 1000 tooffer linear control of therapy temperature changes over the range oftherapy temperatures. By restricting communication between the hot andcold inlets and first channeling the hot and cold fluids to a pre-mixingarea 1106, the restrictor walls enhance the ability of the ball element1000 to effectuate incremental therapy temperature changes.

Automatic temperature control may be achieved using a servo inconjunction with the thermostat discussed above. For instance, thecontrol stem 1305 may be driven by the servo using a step motor with ahome switch, or the like. In this manner, any outlet temperatureprofile, including a linear outlet temperature profile, may be achievedautomatically.

Using automatic control, it may be desirable to tag a lowest possibletemperature to avoid the hunting effect, discussed above. The lowesttemperature may be tagged at, for instance, 55 degrees Fahrenheit inorder to avoid the hunting effect in a broad range of cases. The controlmay also be tailored to each individual's physiology such that thelowest possible temperature is tagged at the tagged just above thetemperature at which the hunting effect is implicated for thatindividual. In this way, the instant invention automatically affords theuser the benefits of cold therapy while avoiding the hunting effect.

Known mixing valves tend to afford the user little temperature control.In general, known valves would afford the user an output therapytemperature that was low, intermediate, or high, with no linear controlthroughout. As a result, the hunting effect could not be avoided in mostcases at the low end, while the most effective cold therapy was notafforded in the intermediate range.

It is also desirable to maintain a constant pressure in the therapy padto present the user with a comfortable feel at the therapy site. Toachieve this, a substantially constant pressure and flow rate must bemaintained in the outlet fluid exiting the mixing valve assembly. Asdiscussed above, a pump may be included between the mixing valve and thetherapy pad. In this manner, a substantially constant output pressureand flow rate may be achieved. However, if the inlet flow resistanceoffered by fluid paths 34 and 42 is substantially different, the flowrates of the respective cold and hot fluids will be effected.

In order to maintain the desired linear outlet therapy temperatureprofile and a constant outlet pressure and flow rate in the presence ofdiffering inlet flow resistances, the size of the wedge shaped inletsmust be adjusted accordingly. It has been found that by making therelative size of the inlets proportional the relative magnitude of theirrespective inlet flow resistances, a linear temperature profile can beachieved while maintaining constant outlet pressure and flow rate. As aresult, any system may be modified to achieve a linear temperatureprofile while maintaining constant outlet pressure and flow rate bytailoring the relative sizes of the inlets proportionally to therespective relative inlet flow resistances. By simply replacing the ballelement of the mixing valve assembly of any system with the instant ballelement tailored to the particular system, the desired results may beachieved.

The mixing valve assembly 1601 of the instant invention may be used toeffectively carry out the method of administering thermal or contrasttherapy. As described above, the method 100 includes providing a volumeof relatively high temperature (hot) fluid at 102 and a volume ofrelatively low (cold) temperature fluid at 104. At 106, the methodincludes selecting relative amounts of hot and cold fluids to mix as atherapy fluid at a desired initial therapy temperature. The methodincludes circulating the therapy fluid with the initial therapytemperature through a therapy pad at 108. A therapy pad is used forillustrative purposes herein. As disclosed above, the present inventionmay be used to provide therapy fluid at a selected therapy temperaturefor any of a variety of temperature therapy devices. The method furtherincludes, at 112, returning the therapy fluid to at least one of thevolume of hot fluid and the volume of cold fluid so as to provide acontinuous flow of therapy fluid at variously selected therapytemperatures.

As shown at 114, the method may also include selecting relative amountsof the hot and cold fluids to mix as a therapy fluid with a desiredthermal or contrast therapy temperature different than the initialtherapy temperature. By changing the relative amounts of hot and coldfluids, the resulting temperature of the therapy fluid may be changed,which changes the therapy received by the therapy recipient.

The ball element 1000 of the instant invention allows the therapyrecipient to have linear control of the temperature of the therapyfluids over the entire range of available therapy temperatures.Selecting relative amounts of hot and cold fluids to mix as a therapyfluid at 114 is achieved by adjusting the rotational position of theinstant ball. The amount of fluid entering the first inlet 1102 andsecond inlet 1101 is determined by the rotational position of the ballelement 1000. This, in turn, determines the therapy temperature of thetherapy fluid leaving the mixing chamber 1211 through the outlet 1212 ofthe ball. The instant invention provides a method for incrementalcontrol of therapy fluid temperature received by the therapy recipient.

The present invention can also be practiced with other techniques forproviding thermal or contrast therapy to a therapy recipient. Forexample, it is possible, using the mixing valve assembly of the instantinvention, to provide therapy fluid at incrementally controllabletherapy temperatures to a variety of therapy devices including soakingbaths, circulation chambers, and the like.

While this invention has been described in terms of several preferredembodiments, there are alterations, modifications, permutations, andsubstitute equivalents, which fall within the scope of this invention.Although sub-section titles have been provided to aid in the descriptionof the invention, these titles are merely illustrative and are notintended to limit the scope of the present invention.

It should also be noted that there are many alternative ways ofimplementing the methods and apparatuses of the present invention. It istherefore intended that the following appended claims be interpreted asincluding all such alterations, modifications, permutations, andsubstitute equivalents as fall within the true spirit and scope of thepresent invention.

1. A mixing valve assembly operable to deliver an output fluid with acomposition determined by a selected ratio of input fluids, saidassembly comprising: an incrementally positionable ball element havingan adjustable rotational position within said mixing valve assembly,said ball having continuously varying restrictive inlets, a mixingchamber in fluid communication with said inlets, and an outlet fordelivery of said outlet fluid, said outlet being in fluid communicationwith said mixing chamber wherein said ball is further characterized byspaced apart interior restrictor walls defining on opposite sidesthereof inlet chambers and between them said mixing chamber wherein saidinterior restrictor walls are disposed between said inlet chambers tochannel fluids from said inlet chambers to said mixing chamber, andwherein; said selected ratio is determined by the rotational position ofsaid ball, and wherein each said opening has a corresponding inlet flowresistance, further wherein each said inlet has a size which isproportional to each said corresponding inlet flow resistance, whereinsaid inlets are substantially wedge shaped, each having a wide forwardedge and a narrow rear apex.
 2. The mixing valve assembly of claim 1,wherein said assembly is operable to deliver a therapy fluid with anoutlet temperature, further wherein said input fluids comprise at leastone relatively high temperature and one relatively low temperaturefluid, wherein said ball further comprises: a first inlet for said hightemperature fluid, a second inlet for said low temperature fluid,wherein; said outlet temperature is determined by said selected ratio.3. The mixing valve assembly of claim 2, wherein said outlet temperatureis controlled by adjusting the rotational position of said ball to giveany desired outlet temperature profile.
 4. The mixing valve assembly ofclaim 3, wherein incremental rotation of said ball gives a substantiallylinear outlet temperature profile.
 5. The mixing valve assembly of claim4, wherein said assembly is operable to deliver said therapy fluid at asubstantially constant outlet pressure and substantially constant outletflow rate.
 6. The mixing valve assembly of claim 5, wherein said secondinlet is larger than said first inlet.
 7. The mixing valve assembly ofclaim 6, wherein said internal restrictor walls include a first walldefining a high temperature inlet chamber and a second wall defining alow temperature inlet chamber.
 8. The mixing valve assembly of claim 7wherein each said wedge shaped inlet extends 140° around thecircumference of said ball.
 9. The mixing valve assembly of claim 8wherein the wide forward edge of said first wedge shaped inlet forms a5° opening at the surface of said ball element, and the wide forwardedge of said second wedge shaped inlet forms a 15° opening at thesurface of said ball element.
 10. The mixing valve assembly of claim 9wherein said assembly is configured to deliver said therapy fluid to atherapy pad.
 11. The mixing valve assembly of claim 10 wherein saidtherapy pad includes an active thermal exchange bladder and an elasticwrap connected to the thermal exchange bladder, further wherein theelastic wrap is configured to adjustably wrap around the thermalexchange bladder and compress the thermal exchange bladder around atherapy site.
 12. The mixing valve assembly of claim 11 furthercomprising a thermostat that automatically selects the ratio of hightemperature and low temperature fluids delivered from the mixing valveassembly.
 13. The mixing valve assembly of claim 12 wherein thethermostat is programmable to automatically change the therapytemperature at a desired time by adjusting the ratio of high temperatureand low temperature fluids delivered form the mixing valve assembly. 14.The mixing valve assembly of claim 13 wherein the thermostat isprogrammed to prevent said outlet temperature from going below a pre-setminimum.
 15. The mixing valve assembly of claim 14 wherein thethermostat is programmed to prevent said outlet temperature from goingbelow 55 degrees Fahrenheit.